A facile approach for the synthesis of spiro naphthalenes by using of nanomagnetic catalyst

A series of functionalized spiro[indene-۲,۲'-naphthalene]-۴'-carbonitrile derivatives were synthesized via a four component reaction including malononitrile, cyclohexanone, aromatic aldehydes and ۱, ۳-indandione in present of Fe۳O۴@SiO۲-NH۲. In this study, a straightforward and efficient method was used for the preparation of magnetic nanoparticles. We have synthesized spiro[indene-۲,۲'-naphthalene]-۴'-carbonitrilederivatives through vinylogous Michael addition. By this simple method, diverse spiro[indene-۲,۲'-naphthalene]-۴'-carbonitrile derivatives have been constructed with excellent yield without any specific isolation. Compared to previous works, the easy separation of the nanocatalyst using an external magnet, reusability, nontoxicity, versatility, high stability of the catalyst, combined with low reaction times and excellent yields, make the present protocol very useful for the synthesis of the title products. The synthesized products and catalyst were confirmed via ۱H NMR, ۱۳C NMR, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), and vibrating sample magnetometer (VSM).

Keywords:

Multicomponent reaction , Michael addition , Knoevenagel condensation , Magnetic nanoparticles , Spiro compounds